In tillage operations, a tractor operator must position the implement with care in order to obtain the proper optimum depth for cultivating. After the implement has been so positioned, it may be necessary to remove the implement from this operating position due to the end of a row being reached or some other operation. The implement operating position will have to be obtained again causing repetition of the optimum depth locating operation by the operator.
In hydrostatically powered tractors, forwardly and rearwardly directed movement is controlled by a single control lever which is moved forwardly or rearwardly to select the appropriate speed and direction of the tractor. The "neutral" position (i.e., where the vehicle is not being driven) is located in the control midway between the full forward and full rearward lever positions.
The use of hydrostatic drive with its inherent need for multiple hand controls becomes of concern when an implement is attached. When the operator has reached the end of a row, for example, the sequence of operations includes slowing the tractor, raising the implement, turning the tractor, lowering the implement, and increasing the tractor speed. Thus the operator must momentarily give up control of either the steering wheel or the hydrostatic drive control to operate the implement. This problem similarly exists when the implement must be constantly adjusted or repositioned while the tractor is moving forwardly in its operating attitude. This is disadvantageous since the practice is unsafe, the operator has more functions to perform and the tractor is momentarily not under complete control.